Print actuating member control mechanism



April 8, 1958 F. J. FURMAN ET Ax. 2,829,592

PRINT ACTUATING MEMBER CONTROL MECHANISM INVENTORS FRANK J. FURMAN OTTO FMONEAGLE ROBERT V. SIMPSON ATTORNE Y BY y@ April 8, 1958 F. J. FURMAN ETAL 2,329,592

PRINT ACTUATING MEMBER CONTROL MECHANISM Filed Dec. 30, 1954 2 Sheets-Sheet 2 FIG.2

INVENTORS FRANK J. FURMAN OTTO F. MONEAGLE ROBERT V. SIMPSON y@ 6. Mw BY ATTORNEY United States Patent PRINT ACTUATING MEMBER CONTROL MECHANISM Frank J. Furman and Otto F. Moneagle, Endicott, and

Robert V. Simpson, Owego, N. Y., assignors to International Business Machines Corporation, New York, N. Y., a corporation of New York This invention relates to printers wherein character impressions are effected through the impact strokes of spring-operated print actuating members and more particularly to mechanisms for controlling such print actuating members.

In high speed wire printers such as is disclosed in our copending application, Serial No. 479,106, led December 3l, 1954, a plurality of simultaneously operable printing mechanisms are arranged in transversely spaced relationship. Each printing mechanism includes a presettable wire matrix print head which is moved towards and away from a recording material by a biased print actuating member in each cycle to effectprinting strokes and laterally of the recording material by other means between printing strokes to enable printing in successive character positions in successive cycles. After a number of such cycles, the printing of a complete line may have been effected by the concurrent operation of each of the print heads.

The main object of this invention is to provide a mechanism to suppress the movement of the print heads during idling periods and others in which no printing takes place in order to reduce the raise level, prevent smudging by the action of the print heads bumping the ribbon against paper, and keep wear and tear at a minimum. An idling period is defined as that time during which the printer is operating but is not being fed data to print. An other period may be a period such as that in which the skip of the paper on a carriage requires more time than is normally provided between successive print head strokes and hence requires that the movement of the print heads be held in abeyance.

Another object of the invention is to provide such a print suppression mechanism which can also be manually adjusted to prevent the operation of certain of said print heads for any desired report or length of time; that is, an operator controlled mechanism which can be used to lock out the operation of any one or more of a line of print heads that is not being used on any particular run of forms.

Still another object of the invention is to provide a print suppression mechanism which is accurate and reliable in operation.

A further object of the invention is to provide such mechanisms which are easy and inexpensive of construction.

In carrying out the invention, a simple mechanism is provided which is capable of selectively suppressing the operation of a complete line of print heads. `There are utilized two similar but spaced cams which are synchronized with the operation of printhammers effective to move corresponding print heads through impact strokes. High portions are provided on these cams which are operative upon corresponding followers to shift a universal bar into the path of and against all of the print hammers if a magnet has been energized. This magnet, when energized, moves interposers carried by the bar at its respective ends into driving engagement with links ice connected with the respective followers. Itresults that if the magnet is energized, the print hammers are prevented from operating, and the print heads do not undergo an impact stroke. Thus, when the magnet is not energized, the universal bar is not moved by the cams and does not interfere with the operation of the line `of print hammers so that printing may be effected in the sub-cycle. p

Suppression of printing by particular printpmechanisms is accomplished by suppressing the operation of the corresponding print heads. Thus, a two-position lever, adjustable between a normal and a second position, is

Y provided for each print hammer. In the rearward position this lever operates through a spring to urge an operating lever to a position in which it is out of the way of the corresponding print hammer. When the two-position lever is shifted to the second or forward position, it urges the operating lever to a position in the path of the corresponding print hammer. It is a feature of this invention that the print hammer whose operation has been suppressed is rendered completely inoperative so as not even to undergo a minimum of impact stroke. In order to accomplish this, the operating lever, which is urged to the position in the path of the print hammer, will usually engage the upper end of the print hammer in its normal position and so be momentarily ineffective to hold the print hammer in an inoperative condition. This condition is quickly terminated, however, as the two-position lever would normally be shifted during an idle period of the printer, and` during this idle period the magnet aforementioned would be energized to operatively connect the cams with the universal bar. The parts are so proportioned that the universal bar undergoes more movement than is necessary merely to block the operation of the print hammers. It is, in fact, moved so far that it shifts all of the print hammers rearwards of their normal position, and it is during this rearward movement that an operatng lever, which has been biased downward by the two-position lever now' shifted to its forward position, slips in front of the corresponding print hammer to block its operation in toto.

It might be observed that the pressures operating on the spring-tired hammers are such as to preclude the ready release of an operating lever from the path of the print hammer when the corresponding two-position lever is shifted to the rearward position. This, too, is buta momentary condition, as such rearward shifting of the two-position lever would also be made during an idling period of the machine, during which the universal bar again would be operating. Thus, the operating lever would be permitted to snap out of the path of the cor-A responding print hammer when the universal bar again moved forward to engage the print hammers, it being recalled that the universal bar originally moved the print hammer sufficiently forward of the forward end of the lever to permit the latter to slip into its obstructing position. t

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention and the best mode which has been contemplated -of applying that principle.

In the drawings:

Fig; 1 is a longitudinal vertical section through a wire printer embodying the invention. t

Fig. 2 is a plan View, partially broken away, of the print hammer control mechanism shown in Fig. 1.

Referring more particularly to the drawings, there is shown in Fig. 1 a wire printer of the type disclosed in the above identified application. In this wire printer, spaced print heads 10, to which are attached guide tubes 12 for print wires 14 to form a character matrix, are

mounted i'n a row across the machine on a transversely slidable carriage 16. The carriage is disposed opposite a platen 20 over which continuous strips 22 of suitable forms may be properlyadvanced for printing thereon a line at a time lby the print wires projecting from the print heads and through the ink ribbon 24. This printing is effected by moving the print heads, from the face of which the print wires forming the desired character patterns have been preset, towards the platen against the ribbon, paper, and platen.

As disclosed in the copending application, print strokes are imparted to the respective print heads through drive wires 26 attached at their rearward ends to the corresponding print heads and guided forwardly therefrom to corresponding print hammers by flexible tubes 28. Each 'tube is fixed at its rearward end to a carriage mounted bracket 29 for the corresponding print head and at its forward end to amounting piece 30 fixed to a transversely extending U-shaped beam 32 in the printer. The wire is driven rearwardly with a controlled velocity through the tube by a print actuating arm 34 to which it is pivotally connected. The print actuating arm is rockably mounted on a transversely extending rod 36 fixed in the printer. Operation vof this print actuating arm, which takes the form of a bell crank having on the free end of its horizontal'arm a roller 38, is controlled by an accurately calculated and machined cam 40 through the action of a spring 42 anchored at one end to the vertical arm of the bell crank 34 and at its other end to a slotted comb 44 xed to the rearward face of the transverse beam 32. This cam, the rotation of which is syn chronized with the operation of the printer, has a normal high dwell 40a which is interrupted by a slight depression 40b into which the roller 3S on the print actuating arm may descend at a controlled rate. Thus, it can be seen that when the depression comes opposite the roller 38, the print actuating arm rotates counterclockwise, as seen in Fig. l, under the bias of the spring 42 and acts to drive the drive wire 26 rearwardly through the guide tube 28. This action in turn is impressed upon the corresponding print head '10 which undergoes a rearward motion orl impact stroke. Since the impression in the cam is of minimum length, the roller is almost immediately forced back upon the high dwell 40a, with the result that the print actuating arm is forced clockwise to pull the drive wire forwardly and retrieve the print head from the recording material. One print actuating arm is provided for each two drive wires and print heads, and a print cam is provided for each print actuating arm, though if desired one continuous cam may be utilized.

It can -be seen that if the operation of the print actuating arms is to be prevented during a cycle, it is necessary to provide a means which is eifective at the time that the rollers 38 normally drop into the depression 40h formed in the respective print cams 40. Accordingly, there is provided a second set of cams 46, one for each side ofthe printer, having high portions 46a which are operative upon corresponding rollers 48 at the same time that the depressions 40b in the print cams 40 move underneath the rollers 38. The rollers 48 are mounted on the free ends of the horizontal arms of bell cranks 50 located at the opposite ends of the transverse rod 36. The upwardly extending arms of these bell cranks are pivotally connected to rearwardly extending horizontal links 52 which are slidably carried through slots 53 by corresponding interposers 54 movable in and out of the orresponding ends of a transversely extending universal The universal bar 56 is supported in the printer upon laterally extending flanges 58a of side bars 58 fixed upon the main frame side plates 60 of the printer. Horizonta-l rollers 61, mounted nteriorly of the ends of the universal bar 'by means of bearing studs 63, locate it in spaced relation to the side bars 58. Only one bearing 61 is provided on each end of the bar to enable the universal bar to cock, thus preventing damage to the guide bars 58, should either of the interposers 54 fail to engage or disengage at some time. Above the universal bar, the side bars are provided with lateral flanges 58b to complete a guide track for the universal bar. In this guide track the universal bar is biased to a rearward position by two pairsof springs 62 located at the respective ends and suitably anchored to it and to brackets 64 lixed to the printer side plates 60. The rearward position to which the springs bias the universal bar is determined by stop screws 66- which are mounted in brackets 68 aiiixed to the upper surface of a plate 70 which overlies the universal bar 56 and is aiiixed at its ends to the upper surfaces. of the sidebars 58. It will thus be observed that the normal position of the universal bar is its rearward one, to which 'it is urged by the springs 62, and that the operation of the bell cranks 5t) will, when rendered effective -by the proper positioning of the interposers 54, be such as to move the universal bar against the upper'ends of the print actuating arms 34 which are also atthat time released by the cams 40 to undergo counterclockwise movements.

`The interposers 54 controlling the operation of the universal bar 56 are slidably mounted in laterally extending holes 72 formed in the side surfaces of the bar near its forward edge. .Each interposer is formed with a round shank 54a which is slidably received in the corresponding hole and at its outer end is iixed to an elongated vertical plate 54h. This plate normally rests exteriorly 0f the corresponding link 52 and is of such size as to be readily receivedin the slot 53 through which the shank 54a extends. It is urged to this exterior position by a compresison spring 74 mounted in the inner end of the laterally extending hole 72. A pin 76, which is fixed to the interposer shank 54a and extends into elongated slots 78 formed above and below the hole 72 in the universal bar, serves to hold the parts together during assembly operations.

As pointed out, the interposers normally are so posi-l tioned that the vertical plates 54b fixed to the outer ends thereof are located exteriorly of the corresponding links 52. The interposers support the rearward ends of the links through pairs of vertically spaced horizontal guide bars 80 xed to the outer surfaces of these links. Thus, a link also is held so'as to receive, in its slot 53, the plate formed on the outer end of the interposer when the same is urged inward when the links are in a rear- Ward position, which is their normal position because of the low dwell of the cams 46. It will thus be evident that a major portion of a sub-cycle is available for the positioning of the interposer plates within the slots 53 formed in the links to render the suppression cams effective to move the universal bar forward when their corresponding bell cranks and links are moved forward.

The movement of these interposer plates 54h into the corresponding links is elected through an energization of a magnet generally indicated by the numeral 82. This magnet is supported upon the upper plate 70 by a bracket 84 lixed to the upper surface of the plate and to the closed end of the magnet yoke 82a. On the other end of the yoke, an armature 82h is pivoted by means of a pin 82C received in a slot (not shown) formed in the yoke. This pin is held in the slot by means of a bracket 82d fixed to the yoke. The armature is pivoted to a normal or open position in the clockwise direction (Fig. 2) by means of a spring 82e acting upon an extension 82,t of the armature and anchored at its other end to a iiange 82g integral with the bracket 82d. Thus, when a magnet coil 82h is energized, it swings the armature `82h counterclockwise (Fig. 2) towards a core 82]' until it strikes the residual material 82k on the yoke, which is effective to maintain it in spaced relation to the core of the magnet. This l'action of the magnet armature is used to position the interposer plates 54b within the links 52.

e As best seen in Fig. 2, the armature acts upon the ol- `set end 86a of a lever 86 pivoted tov theunderside of the top plate 70 by means of a stud bolt 88. The opposite ends of this lever are pivotallyconnected to links 90 which, at their other ends, arepivotally connected to lugs 92a formed on the intermediateportions of levers 92 pivoted at their rearward ends upon stud bolts 94 also fixed to the top plate 70. The other or free ends of these levers are biased by springs 96, anchored at their other ends to studs 9d depending 4from the top plate, to positions in which they enable the interposer plates 54b to be biased clear of the corresponding links 52 by the `compression springs 74. When the magnet 82 is energized and the armature swung counterclockwise (Fig. 2), the lever 86 is rotated clockwise pulling the links 90 interiorly and `swinging the levers 92 against the bias of the springs 96 to where they strike and force the interposer plates 54h into the slots 53 formed in the links 52. The location of the ends of these levers is such that, when the links are moved forwardly and move the interposer plates forwardly, they remain in contact with the plates, thus insuring a positive drive during reciprocation of the links. Of course, the movement of the interposer plates also causes forward movement of the interposer shanks 54a to which they are attached and, in turn, forward movement of the universal plate 56. The action of the two interposers is simultaneous such that a uniform forward motion is imparted to the universal bar, and its range of movement is such as to strike all of the print actuating arms 34 and displace them slightly forward. In normal operation this forward displacement of the print hammers will be a momentary thing coinciding in duration with the length of time that it normally takes the depression formed in the print cams to pass underneath the print hammer rollers. Thus, when the universal bar restores because the rollers 48 drop off of the high points of the cams 46a, the normal high dwells 40a of the print cams 40 will again be opposite the rollers 38 so` that the print hammers undergo only a slight rearward movement.`

The suppression of operation of only particular print hammers is effected by shifting corresponding two-position levers 100. These levers, formed as U-shaped mem.- bers by bending over the ends 100:1 of at members, are pivoted by these ends on a pin 102. They are also provided with bent-over side portions 10017 which provide flat surfaces by which they may be conveniently engaged by the fingers of an operator. The pivoted ends 100:1 of the levers terminate in a point from which edges 100e` and 100d recede. These edges are each of a length sulficient to extend beyond a perpendicular passing through the center of the pin 102 on which the corresponding lever is mounted, with the result that by mounting this pin in a spring member 104 bolted to the surface of the upper plate 70, the two-position lever will beheld in one or the other of two positions, these positions being determined by the engagement of one or the other of the receding edges` 100e and 100:1 with the surface of the upper plate 70. The point on the lever ends 100a thus forms a sliding fulcrum point about which the levers are moved, and the spring members 104 form off-center devices holding the levers in whichever position they are manually placed.

The levers 100 control respectively operating levers 106 which are also mounted on the pins. Each lever is formed with a generally horizontal forward portion having a down-turned lip 106g. formed as two vertical side portions 106b suitably apertured to pivotally accommodate the lever on the pin 102. At their upper end, these vertical side portions are connected by a pin 107, Fig. 2, to provide an anchor for one end of a tension spring 108, the other end of which is anchored to a hook 100e formed by depressing a partially severed portion at the top of the lever 100. The upstanding operating lever portions 10611 are of less length At its rearward end each lever isV 6 than the lengthof` the two-position lever ends :1; hence, when the two-position lever `100 is .shifted from one to another position, it exerts a pull on the operating lever 106 urging the latter in the same direction that it was moved.

As has been pointed out, the normal position of the two-position levers 100 is the rearward one. When it is desired to suppress the operation of a particular print hammer, the corresponding two-position lever 100 is shifted to its forward or other position and, in accordance with the operation already explained, moves the print hammer controlling lever 100 in the clockwise direction, as seen in Fig. 1. This would normally place the downturned lip 106a of the lever 106 on the upper edge of the corresponding print actuating arrn34, as the print hammer has a normal position forward of the position to which it is momentarily moved by the universal bar 56. This movement occurs immediately, however, as in the normal operation of the printer the adjustment of a twoposition lever 100 would only be made during an idling period of the printer.` As previously explained, during such idling periods the universal bar is operating, and hence, later in the same sub-cycle or in the one immediately following, the print hammers would be moved forwardly to where the print hammer corresponding to the two-position lever which has been adjusted permitted the corresponding operating lever 106 to slip 'in behind it. Thus, when the universal bar recedes, the print hammer would be intercepted and held in this intercepted position. It may be observed that, as now intercepted, the print actuating arm roller 3S rides clear of even the high dwell 40a on the print cam 40, as is shown in Fig. l, thus reducing wear and tear, the loading on the printer, as well as its noise level. p,

When it is desired to restore a print hammer to operating condition, the two-position lever 100 is shifted rearwardly. This may or may not be followed by an immediate return of the corresponding operating lever 106, as it depends on the positioning of the universal bar at this time. Normally this restoring of the two-position lever would be accomplished during an idle period of the machine, and hence the universal bar` will be operating in each sub-cycle. The operation of the universal bar is necessary to a restoration of the print hammer controlling lever, as the normal spring forces acting upon the print hammer are such that the friction between the print hammer and the down-turned lip 106a on the lever are greater than the effective forces which can be induced in the tension spring 108 by the shifting of the two-position lever 100. Hence, the print hammer controlling lever remains in the print hammer intercepting position until such time as the universal bar is operated and moves the corresponding print hammer slightly rearward of its obstructed position. lt will be apparent, therefore, that the shifting of the two-position lever 100 normally is soon followed by a shifting of the print hammer controlling lever, and since machine sub-cycles pass very quickly, it will be evident that such adjustment would be effected before an operator who tlipped the two-position lever back to its normal position could initiate printing operation of the printer.

While there have been shown and described and pointed out the fundamental novel features of the` invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art, without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is: i

l. In a print actuating member control mechanism, a print actuating member biased to effect print strokes, rst means cyclically operable to release said printactuatng member for biased movement and thereafter to restore it,

Vsecond means operable in step with said first means, third means movable from a normal position out of the path of ysaid print actuating member to a position in which it obstructs biased movement of said print actuating inember, and fourth means operable to connect said third means to said second means so that the third means may be moved to the obstructing position.

2. In a print actuating member control mechanism, a print actuating member biased to effect print strokes, first means cyclically operable to release said print actuating member and thereafter restore it, second means operable in step with said first means, third means biased to a normal position and movable therefrom to an obstructing position in the path of the print actuating member, fourth means positionable to connect' said third means to said second means for movement from the normal to the obstructing position, and means selectively operable to position the fourth means.

3. In a print actuating member control mechanism, a

print actuating member biased to effect print strokes, cam means cyclically operable to enable said print actuating member to undergo biased movement and thereafter effective to restore it, second means operable in step with said cam means, third means movable from a normal position out of the path of said print actuating member to an obstructing position in the path of said print actuating member, and fourth means for connecting said third means for movement by said second means from the normal -to the obstructing position.

4. In a print actuating member control mechanism, a print member biased to effect print strokes, cam means cyclically operable to release said print actuating member and thereafter restore it, a second cam means operable in step with said first cam means, third means movable from a normal position out of the path of said print actuating member to a position in which it obstructs the biased movement of said print actuating member, and fourth means for optionally connecting said third means to said second means for movement from the normal to the print member obstructing position.

5. In a print actuating member control mechanism, a print actuating member biased to effect print strokes, first cam means cyclically operable to release said print actuating member and thereafter restore it, second cam means operable in step with said first cam means, a follower for said second cam means, third means biased to a normal position out of the path of said print actuating member but movable therefrom to a position in which it obstructs the biased movement of said print actuating member,

and fourth means optionally operable to connect said third means to said cam follower for movement from its normal position to its print actuating member obstructing position.

6. In a print actuating member control mechanism, a print actuating member biased to effect print strokes, first cam means cyclically operable to release said print actuating member and thereafter restore it, second cam means operable in step with said first cam means, a follower for said second cam means, third means biased to a normal position out of the path of said print acv tuating member but movable therefrom to a position in which it obstructs the biased movement of said print actuating member, a link pivotally connected with said cam follower, and means optionally operable to connect said third means with said link for movement from the normal position to the print actuating member obstructing position.

7. In a print actuating member control mechanism, a print actuating member biased to effect print strokes, first cam means cyclically operable to release said print actuating member and thereafter restore it, second cam means operable in step with said first cam means, a follower for said second cam means, third means biased to a normal position out of the path of said vprint actuating member but movable therefrom to a position in which it obstructs the biased movement of said print actuating member, a link pivotally connected with said cam follower, an elongated opening through said link, an interposer element carried by said third means for cooperation with said opening in said link, and means optionally operable to move said interposer element into the elongated opening of said link so that the latter is effective when the second cam means is operated to move the third means from the normal position to the print actuating member obstructing position.

8. In a print actuating member control mechanism, a print actuating member biased to effect print strokes, first means cyclically operable to release said print actuating member and thereafter restore it, second means operable in step with said first means, third means movable from a position out of the path of said print actuating member to a position in which it has engaged said print actuating member and shifted it to a position in which it is out of the control of said first means, fourth means optionally operable to connect the third means with the second means, and other means movable from a normal position to a position in which it rides on top of said print actuating member until the latter is shifted by said third means to the position in which it is out of the control of the first means and whereupon it may slip into the path of biased movement of said member to obstruct it and maintain it out of the control of the first means.

9. In a print actuating member control mechanism, a print actuating member biased to effect print strokes, first means cyclically operable to release said print actuating member and thereafter restore it, second means operable in step with said first means, third means movable from a position out of the path of said print actuating member to where it engages said print actuating member and shifts it out of the control of said first means, fourth means optionally operable to connect the third means with the second means, a first lever having two positions, a second lever having a position out of the path of said print actuating member when said first lever is in one of its positions, a spring connecting said second lever to said first lever for urging to its one position when said first lever is in the corresponding position, said spring being effective when the first lever is shifted to its other position to urge said second lever into the path of said print actuating member, said second lever when urged into the path of said print actuating member normally engaging the top of said member and moving to a position in the path of said member when the fourth means is operated to connect the third means with the second means.

10. In a print actuating member control mechanism, a print actuating member biased to effect print strokes, first means cyclically operable to release said print actuating member and thereafter restore it, second means operable in step with said first means, third means movable from a position out of the path of said print actuating member to where it engages said print actuating member and shifts it out of the control of said first means, fourth means optionally operable to connect the third means with the second means, a pin, a U-shaped lever having the free ends of its arms mounted on the ends of said pin, a support, a spring fixed to said support and urging said pin toward said support to where the ends of said lever engage said support, intersecting edges formed on the free ends of said lever rendering the lever stable in either of two positions, a follower lever, a lug on said lever located between the two alternative positions of said U- shaped lever, a spring connecting said lug to a part of said U-shaped lever having positions on the outside of it in the alternative positions of said U-shaped lever, said U-shaped lever in one of its positions so acting on said follower lever as to urge it to a normal position out of the path of said print actuating member and in its other position urging said follower lever to a position in the path of said print actuating member, said print actuating member having a normal position in which it intercepts asf-.ideas the biased movement of said follower lever, said third means being effective when the fourth means is operated to connect it with the second means to move said print actuating member against its bias to where the follower lever slips into its path and is effective to hold it out of engagement with the lirst means when the fourth means is inoperative.

11. In a print suppression mechanism, a plurality of print actuating members each biased to undergo print strokes, first means cyclically operable to release said print actuating members for biased movement and thereafter restore them, second means operable in step with said first means, a bar having a normal position out of the path of biased movement of said print actuating members but movable to a position in which it obstructs the biased movement of all of said print actuating members, and means optionally operable to connect said bar to said second means for movement from the normal position to the print actuating member obstructing position.

12. In a print suppression mechanism, a plurality of print actuating members each biased to effect print strokes, cams for the respective print actuating members each simultaneously effective to release the corresponding print actuating member and thereafter to restore it, a universal bar biased to a normal position out of the path of said print actuating member but movable to a position in which it obstructs the biased movement of all of said print actuating members, cam means effective in step with the print actuating member releasing cams, and means optionally operable to connect the universal bar to said cam means for movement from the normal position to the print lactuating member obstructing position.

13. In a print suppression mechanism, a plurality of print actuating members each biased to effect print strokes, cams for the respective print actuating members each simultaneously effective to release the corresponding print actuating member and thereafter to restore it, a universal bar biased to a normal position out of the path of said print actuating members but movable to a position in which it obstructs the biased movement of all of said print actuating members, cam means at each end of said universal bar and effective in step with the print actuating member releasing cams, and means optionally operable to connect said cam means with the corresponding ends of the universal bar to move the bar from its normal position uniformly to its print actuating member obstructing position.

14. In a print suppression mechanism, a plurality of print actuating members each biased to effect print strokes,

cams for the respective members each simultaneously effective to release the corresponding member and thereafter to restore it, a universal bar biased to a normal position out of the path of said members but movable to position in which it obstructs the biased movement of all of said members, a cam adjacent each end of said universal bar, a follower for each of these last two cams, a link pivotally connected to each of said followers, an opening in each of said links, an element carried by said universal bar at each of its ends and having a normal position out of said link opening but movable to a position in said link opening which renders it and the bar movable with said link, and means optionally operable to simultaneously move said interposer elements into the corresponding links.

l5. In a print suppression mechanism, a plurality of print actuating members each biased to effect print strokes, cams for the respective members each simultaneously effective to release the corresponding member and thereafter to restore it, a universal bar biased to a normal position out of the path of said members but movabie to a position in which it obstructs the biased movement of all of said members, a cam adjacent each end of said universal bar, a follower for each of these last two cams, a link pivotally connected to each of said followers, an opening in each of said links, an element slidably accommodated in laterally extending openings formed in said universal bar and extending through the opening in said link, said opening and said element being so proportioned as to accommodate all the relative motion induced in said link by the corresponding cam follower, a part formed on the end of each of said elements, said part being of such size as to be receivable in said link opening when said element is moved into the corresponding bar opening, said links being formed with laterally extending flanges whereby the links are supported on said elements and the parts are guided into said link openings, and means operable to simultaneously depress said elements into the universal bar `openings to where the parts are received in said link openings.

16. In a print suppression mechanism, a plurality of print actuating members each biased to effect print strokes, cams for the respective members each simultaneously effective to release the corresponding member and thereafter to restore it, a universal bar biased to a normal position out of the path of said members but movable to a position in which it obstructs the biased movement of all of said members, cam means effective in Step with the member releasing cams, means optionally operable to connect the universal bar to said cam means for movement from the normal position to the member obstructing position, and a lever for each of the members adjustable between a normal position in which it is out of the corresponding print actuating member path and to a second position in which it obstructs the path of biased movement thereof.

17. In a mechanism, a driving element, a link pivotally connected at one end to said driving element, an elongated opening formed in said link, a part biased to a normal position, a laterally extending opening formed in said part, an element slidably mounted in said part opening and extending through the opening in said link, an interposer element mounted on the end of said element projecting through said link, said interposer part being so shaped as to be slidably receivable in the link opening, and flanges formed on said link adjacent said opening to support said link on said interposer part and guide said interposer part into the link opening.

18. A toggle lever arrangement comprising a supporting surface, a pin, a U-shaped part having the ends of its arms pivoted on the pin, a spring for urging said pin towards the supporting surface, straight edges intersecting each other formed on the ends of the arms of said U- shaped part and so that corresponding ones on the respective arms may be simultaneously seated on the supporting surface, said edges being so located that when they rest on the supporting surface the spring-biased pin will be centered thereover.

References Cited in the iile of this patent UNITED STATES PATENTS 

